The Lander Pivot Screw holds the pivot in place on the back of the knife. It's an important job that not any old screw can do. This one is a T8, and the part number is P0053-1.
We recommend adding a drop of Blue Threadlocker to the screws when reassembling your knife. This will prevent your screws from sneakily escaping into the abyss. When it comes to the pivot screw, we can't stress this enough. Put some Blue Loctite on it. Ain't nobody got time for lost knife screws. Or is it knaf screws? Same same.
You're going to need a T8 driver bit to reassemble. We gotchoo'. Try this torx tool with Wiha bits. It's our favorite.